In some cases the therapeutic value of a pharmaceutical is dependent upon delivery of a dose tailored to the individual. An adult male weighing 150 pounds (68 Kg) could require only 80% of the dose for someone weighing 185 pounds (84 Kg). In some cases, slight overdosing does not have any negative therapeutic affects. However, for some medicines and for certain individuals who are sensitive to pharmaceuticals in general, administering the precise dose can be a health concern. Also, some pharmaceuticals are very expensive so that even if a 30% overdose does not harm the patient in any way, the excess pharmaceutical being dispensed can be quite costly. Therefore, for maximum therapeutic effectiveness and to avoid problems associated with over or under medicating a patient, the dose of some pharmaceuticals should be accurately adjusted to the particular patient.
Pharmaceuticals which are injected or given orally in liquid form can be quite accurately dispensed as to dose. However, many pharmaceuticals are dispensed in pill form. While pill cutters can be used to halve or quarter many pills, this somewhat messy process does not provide a great deal of flexibility for accuracy in dosage.